title: Simulation of a current source with a Cole-Cole load for multi-frequency electrical impedance tomography.
abstract: An accurate current source is one of the keys in the hardware of Electrical impedance Tomography systems. Limitations appear mainly at higher frequencies and for non-simple resistive loads. In this paper, we simulate an improved Howland current source with a Cole-Cole load. Simulations comparing two different op-amps (THS4021 and OPA843) were performed at 1 kHz to 1 MHz. Results show that the THS4021 performed better than the OPA843. The current source with THS4021 reaches an output impedance of 20 MΩ at 1 kHz and above 320 kΩ at 1 MHz, it provides a constant and stable output current up to 4 mA, in the complete range of frequencies, and for Cole-Cole (resistive and capacitive) load.
authors.forename: Susana
authors.initials: S
authors.lastname: Aguiar Santos
authors.forename: Thomas
authors.initials: T
authors.lastname: Schlebusch
authors.forename: Steffen
authors.initials: S
authors.lastname: Leonhardt
mesh_terms: D000465:Algorithms; D000669:Amplifiers, Electronic; D002138:Calibration; D003198:Computer Simulation; D017097:Electric Impedance; D004560:Electricity; D006801:Humans; D008168:Lung / Q000473:pathology; D014054:Tomography / Q000379:methods*